Slotted rail terminal

Abstract

A slotted rail terminal for highway guardrails. The rail of the terminal contains at least one slotted section extending along the rail and having at least one longitudinal slot of a size sufficient to reduce the ability of the rail to resist bending in response to a loading from one end or the side of the rail. A slot guard is provided which is adapted to be attached to the rail on the side facing away from the highway and downstream of each slotted section relative to expected longitudinal loadings on the rail. The slot guard is configured to abut the rail and span its respective slotted section so as to resist enlargement of each slot. The slot guard enables the slotted section to resist and oppose lateral impacting forces such that the slotted section of the guardrail will act to substantially redirect laterally impacting vehicles.

What is claimed is: 
     
       1. A highway guardrail terminal for extending along a roadway and having an upstream portion and a downstream portion, said terminal comprising: (a) a longitudinally corrugated rail having upper and lower peaks and a valley between the peaks;   (b) at least one slotted section extending along the rail and comprising at least one longitudinally disposed slot in the rail of a size sufficient to reduce the ability of the rail to resist buckling in response to a longitudinal loading from one end of the rail; and   (c) a slot guard attached to the rail proximate the downstream portion of said at least one slotted section relative to longitudinally disposed loadings on the rail, wherein said slot guard extends along the rail toward said upstream portion and comprises a deflector portion which diverges at an angle away from said rail.   
     
     
       2. The guardrail terminal of claim 1, wherein the slot guard comprises a central portion abutting the valley of the rail, and opposed wing portions abutting opposing sides of the valley. 
     
     
       3. The guardrail terminal of claim 2, wherein said deflector portion is proximate an end of the central portion and extends at said angle away from the central portion. 
     
     
       4. The guardrail terminal of claim 1, wherein said slot guard has an upstream end which overlaps a downstream portion of said at least one slotted section. 
     
     
       5. The guardrail terminal of claim 1, wherein the rail is substantially parallel to the roadway. 
     
     
       6. The guardrail terminal of claim 1, wherein the rail is flared at its upstream end away from the roadway. 
     
     
       7. The guardrail terminal of claim 6, wherein the flare is substantially parabolic. 
     
     
       8. The guardrail terminal of claim 6, wherein the flare is substantially straight. 
     
     
       9. The guardrail terminal of claim 1, wherein said at least one slotted section comprises three longitudinal slots cut into the rail, one of said slots being located proximate the valley of the rail, and one of said slots being located proximate each peak of the rail. 
     
     
       10. The guardrail terminal of claim 9 wherein said at least one slotted section comprises multiple slotted zones longitudinally spaced along the rail. 
     
     
       11. The guardrail terminal of claim 9, wherein said slots are about 1/2" wide and at least 12" in length. 
     
     
       12. The guardrail terminal of claim 1 wherein the downstream portion is adapted to be fixedly connected to an adjoining guardrail. 
     
     
       13. The guardrail terminal of claim 1 further comprising one or more support posts supporting the rail. 
     
     
       14. The guardrail terminal of claim 13 wherein at least one of the posts is a frangible post. 
     
     
       15. A highway guardrail terminal adapted to be placed alongside a roadway having an upstream portion and a downstream portion, said terminal comprising: (a) a corrugated guardrail having upper and lower peaks and a valley between the peaks, said guardrail also having an upstream portion and a downstream portion and being supported by at least one frangible support post so that the downstream portion is adapted to be fixedly connected to an adjoining guardrail, said guardrail further being installed on a flare wherein the offset of each support post away from the roadway is increased as the rail process upstream;   (b) at least one slotted section between each support post, said slotted section comprising three longitudinally disposed slots in the guardrail, one said slot being located in the valley of the guardrail, and one of each said slots being located in either peak of the guardrail; and   (c) a slot guard attached to the guardrail on the side facing away from the roadway and proximate said slotted section, said slot guard comprising a central portion abutting the valley of the rail, opposed wing portions abutting opposing sides of the valley, and a deflector attached to the central portion and extending at an angle away from the central portion.   
     
     
       16. A highway guardrail terminal for extending along a roadway and having an upstream portion and a downstream portion, said terminal comprising: (a) a longitudinally corrugated rail having upper and lower peaks and a valley between the peaks;   (b) at least one slotted section extending along the rail and comprising at least one longitudinally disposed slot in the rail of a size sufficient to reduce the ability of the rail to resist buckling in response to a longitudinal loading from one end of the rail; and   (c) a slot guard attached to the rail proximate the downstream portion of said at least one slotted section relative to longitudinally disposed loadings on the rail, said slot guard comprising a central portion abutting the valley of the rail and opposed wing portions abutting opposing sides of said valley, said slot guard further comprising a deflector proximate an end of said central portion and extending at an angle away from said central portion.   
     
     
       17. The guardrail terminal of claim 16 wherein said slot guard has an upstream end which overlaps a downstream portion of said at least one slotted section. 
     
     
       18. The guardrail terminal of claim 16 wherein the rail is flared at its upstream end away from the roadway. 
     
     
       19. The guardrail terminal of claim 16 wherein the slotted section comprises three longitudinal slots cut into the rail, one of said slots being located proximate the valley of the rail, and one of said slots being located proximate each peak of the rail.